Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
  • H05B41/14—Circuit arrangements
  • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
  • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
  • H05B41/288—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps without preheating electrodes, e.g. for high-intensity discharge lamps, high-pressure mercury or sodium lamps or low-pressure sodium lamps
  • H05B41/2885—Static converters especially adapted therefor; Control thereof
  • H05B41/2887—Static converters especially adapted therefor; Control thereof characterised by a controllable bridge in the final stage
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
  • H05B41/14—Circuit arrangements
  • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
  • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
  • H05B41/14—Circuit arrangements
  • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
  • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
  • H05B41/288—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps without preheating electrodes, e.g. for high-intensity discharge lamps, high-pressure mercury or sodium lamps or low-pressure sodium lamps
  • H05B41/292—Arrangements for protecting lamps or circuits against abnormal operating conditions
  • H05B41/2928—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the lamp against abnormal operating conditions
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
  • H05B41/14—Circuit arrangements
  • H05B41/36—Controlling
  • H05B41/38—Controlling the intensity of light
  • H05B41/39—Controlling the intensity of light continuously
  • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
  • H05B41/3921—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations
  • H05B41/3925—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations by frequency variation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Definitions

• the present invention relates more generally to the field of public lighting installations which comprise a plurality of lamp posts, for example street lighting installations, and communication means for switching on, switching off and modulating them individually or in selective groups. More particularly, the present invention relates to a method for driving discharge lamps, supplied by an alternate current electrical supply network, by supplying the minimum possible number of starting pulses (typically just one) in the switch-on phase and regulating their steady- state luminosity. In still greater detail, the invention relates to a method for driving and an associated command and control device for discharge lamps, for example high pressure sodium lamps, such as may equip the lamp posts of public lighting installations, but may also be used in industrial or the municipal sector for lighting areas or car parks of a relatively extensive area. Background of the invention
• These bulbs are usually made from quartz and filled with various types of gas which are capable of supporting the flow of electric current once they have been brought to a particular state of excitation, known as ionisation, in the switch-on phase.
• gas molecules once electrically charged (preionisation phase), undergo a change in their electrical state, changing from an insulator to a conductor. In this latter state, they can thus permit the flow of electric current in exchange for strong light emission which usually arises due to a thermoelectric effect.
• the current may thus be externally controlled by means of appropriate electrical driving circuits, with the aim of regulating steady-state light emission, in terms of both wavelength (spectrum) and intensity (lumens per m 2 - i.e. lux - or W per m 2 , depending on the reference variable stated in the regulations).
• the currently most widespread lamps in fact comprise lamp posts with a lamp 2 connected in series to a current-limiting coil 3 and to an appropriate ignitor 4 which functions as a starter for the gas preionisation phase; this arrangement is connected to the general 230 V AC electrical supply network, as shown schematically in Figure 1.
• the lamps are generally rated at 150 W, although there are installations of up to 2000 W. It should also be noted that HPS sodium lamps behave overall very differently from xenon lamps.
• the emitted light spectrum is in fact very different, sodium lamps virtually completely lacking the ultraviolet component and instead comprising a very strong yellow/ orange component which also characterises their appearance in the streets or squares where they are usually installed.
• gas excitation always proceeds by means of a high intensity electric field and that this makes it possible to "detach" some atoms from the material constituting the lamp electrodes resulting their actually being eroded and, ultimately, physically consumed; it is never possible to switch the lamps back on without having allowed a cooling time which may in some cases extend to several minutes; it is not possible to switch the lamps on if the supply voltage is less than 195 V AC; in contrast, it is possible to keep them switched on at voltages of as low as approx. 180 V AC; if the supply voltage is raised to approx. 250 V AC, electrical efficiency drops fairly quickly and assumes an average value of 65%.
• the technical problem underlying the present invention is that of devising a command and control device for discharge lamps, for example high pressure sodium lamps, which has structural and functional characteristics such as to permit only active power to be drawn from the electrical network; in this manner, the efficiency of said electrical distribution network would be maximised.
• a command and control device for discharge lamps for example high pressure sodium lamps, which has structural and functional characteristics such as to permit only active power to be drawn from the electrical network; in this manner, the efficiency of said electrical distribution network would be maximised.
• Another object of the invention is to conceive a command and control device for discharge lamps which has structural and functional characteristics such as to permit the lamp to be driven at high frequency by controlling and regulating the voltage and current drawn and cutting any continuous current component absolutely to zero with the aim of maximising the average life of said lamp.
• a further object of the invention is to be able to regulate luminous flux at will, as a function of the state of ageing of the lamp, so specifically enabling programmable light emission.
• Another object of the invention is to permit the lamp also to be switched on at voltages below those which are currently possible, eliminating the waiting time for immediately switching back on and so actually allowing it to be switched back on when hot (hot restart).
• an object of the present invention is, not least, to maximise the electrical efficiency of the command and control device for discharge lamps, also minimising operating temperatures and structural dimensions, with an aim of above all reducing the quantity of electrical energy necessary for achieving the radiation specified in international regulations.
• the concept on which the present invention is based is that of providing that the lamp be driven at relatively high current and switching frequencies.
• the problem is solved by using a microprocessor capable, on the input side, of measuring the current drawn by the lamp and, on the output side, of driving one or more power switches for high frequency switching of the current in the lamp.
• said electronic microprocessor which receives on the input side data regarding the current drawn by the lamp and is connected on the output side to a stage incorporating at least one power switch for high frequency switching of the alternate current supply to the lamp, characterised in that said electronic microprocessor effects control and regulation of the power taken from the electrical supply network by regulating the current drawn such that it follows a sinusoidal course in phase with a reference waveform adapted to the network voltage which is measured from time to time and by changing continuously the driving frequency through the lamp switch- on period.
• the present invention also relates to a command and control device for a discharge lamp, for example a high pressure sodium lamp, supplied by an alternate current electrical supply network, of the type intended to supply a starting pulse to the lamp in the switch-on phase and to regulate the luminosity of the lamp in the steady state
• said device comprising an electronic processor receiving on the input side data regarding the current drawn by the lamp and connected on the output side to a stage incorporating at least one power switch for high frequency switching of the alternating current supply to the lamp, characterised in that said electronic microprocessor effects control and regulation of the power taken from the electrical supply network via a PFC block by regulating the current drawn such that it follows a sinusoidal course in phase with a reference waveform adapted to the network voltage which is measured from time to time and by changing continuously the driving frequency through the lamp switch-on period.
• the switching frequency is variable in a range of between 20 kHz and 75 kHz.
• control is effected by a closed loop with a loop gain which varies as a function of the course said network voltage.
• driving proceeds at variable frequency in such a manner as to make it extremely straightforward to implement the controller by means of a DSP (Digital Signal Processor) type microprocessor capable of controlling current supply to the lamp with automatic cutoff in the event of overcurrent or excessive difficulty in starting (lamp at end of life) .
• the command and control device adopts an input power factor correction (PFC) stage or block which, apart from ensuring only active power is drawn from the network, also makes it possible to make a stabilised voltage available with which to supply the subsequent stage.
• PFC input power factor correction
• the device of the present invention is capable of delivering the same power demanded by lamp entirely independently of the prevailing network voltage (and frequency); this makes it possible to install the device of the present invention in any location without having to worry about the characteristics of the local electrical supply network.
• the lamp may be activated by means of a half-bridge stage, a single power transistor (single ended) stage or a full-bridge stage, but in any event always at high frequency and with resonance to cut switching losses absolutely to zero. Any continuous component in lamp current is completely eliminated with any one of these circuit topologies.
• Figure 1 shows a schematic view of a sodium lamp ignitor of known type
• Figure 2 shows a schematic block diagram of a device embodied according to the present invention for the command and control of discharge lamps
• Figure 3 shows a schematic view of a detail of the device of Figure 2;
• Figure 4 shows a schematic view of an output stage of the device according to the invention and of its connections with an HPS lamp;
• Figure 5 shows a schematic view of a detail of a line filter incorporated in the device according to the invention;
• Figure 6 shows a perspective view of a prototype of the device of Figure 2; - Figure 7 shows a schematic view of a public lighting installation in which the luminaires or lamp posts are each equipped with the device of Figure 2.
• 1 denotes overall and schematically a command and control device embodied according to the present invention for discharge lamps 2, for example high pressure sodium lamps, also known by the abbreviation HPS.
• discharge lamps 2 for example high pressure sodium lamps, also known by the abbreviation HPS.
• Such lamps 2 may be used in various fields of application, for example they may equip lamp posts 5 of public lighting installations or they may also be used as a fixed luminaire in the industrial or municipal sector for illuminating areas or car parks of a relatively extensive area.
• the command and control device 1 for discharge lamps 2, for example sodium lamps HPS, is installed between the lamp and an alternating current electrical supply network 8 and supplies the minimum number of starting pulses (typically just one) to the lamp in the switch-on phase and regulates its steady-state luminosity.
• Said device 1 comprises a microprocessor 7 which, on the input side, measures the current I drawn by the lamp and, on the output side, drives an inverter stage 25 incorporating one or more power switches 6 for high frequency switching of the current in the lamp.
• the switch 6 may be, for example, a MOSFET power transistor.
• the command and control device 1 will also be defined below by the term electronic ballast and essentially comprises the following functional blocks incorporated on a single circuit board: a supply block 13 with line filter, with "Green Mode” functionality, connected to an electric power distribution network (90-265 V); a DSP (Digital Signal Processing) control microprocessor 7, which comprises: a. a portion for controlling and regulating the power taken from the electrical network; b. a portion for controlling and regulating the current in the lamp 2; c. a portion for controlling the starting phase of the lamp 2; d. a portion dedicated to electrical measurements and data storage; e.
• a portion for managing light profiles a power factor correction (PFC) block 10 closely associated with the processor 7; an output stage 25 with one or more power switches 6 connected, on the input side, to one or more driving outputs of the microprocessor 7 and, on the output side, to the lamp 2 via an injector block 11; a digital signal analysis modem 15 for power line communication (PLC) control 16 to permit connection with a remote management unit 14 in cooperation with the processor 7.
• PFC power factor correction
• the supply block 13 is connected directly to the electrical supply network L, N and its architecture and functionality are such as to reduce stand-by consumption in accordance with European and American regulations, which are currently not mandatory, such as: "Code of Conduct” and "Energy Star”.
• the block 13 supplies the processor 7, the modem 15 and the power correction block 10.
• the supply 13 is constructed as a line filter and incorporates an LC controller known as a "Green Mode Supply”, but also makes use of specific operational management determined by the operating status of the microprocessor 7 and the controller 16.
• the execution status of the DSP microprocessor 7 and of the PLC control device 16 is subdivided into two modes: active status stand-by status Status is considered “active" when the electronic ballast 1:
• the status is deemed to be "stand-by".
• the power consumption of the two microprocessors 7 and 16 is such that both must be maintained under low power draw conditions to reduce overall current consumption.
• a specific operating scheme in stand-by status has been devised to meet the requirements both of low consumption and of responsiveness of the device 1 on receiving a command.
• both of the processors 7, 16 are "woken up", i.e. put into active status with their associated nominal consumption, for each network period.
• ZCD zero-crossing detector
• a command is sent from the remote management unit 14 which forces the device into one of the following states:
• the DSP microprocessor 7 is a hardware component capable of carrying out the following measurements by means of the previously listed control portions: 1) measurement of input network voltage 2) measurement of the high frequency component of the input current
• Oversampling is generally used to reduce the noise component in the measurements: assuming oversampling of 100%, this means that an ADC with a conversion time of less than 5.88 ⁇ s/ sampling must be used. This limit means that the DSP must complete an evaluation loop in a time which is less than twice the maximum determined, comprising all the control loops which are present.
• the PFC block 10 associated with the microprocessor 7 operates at a switching frequency which is approximately twice that of the lamp 2 supply.
• the DSP microprocessor 7 controls and regulates the power taken from the public distribution network working in close cooperation with the block 10 and according to a PFC (Power Factor Correction) mode which is made possible by the presence within the block 10 of a bridge circuit 12, an LPFC coil inductor, a semiconductor power device, for example a MOSFET power transistor M and a diode D, connected as shown in Figure 3.
• PFC Power Factor Correction
• the DSP microprocessor 7 carries out the function of regulating the current drawn from the network in such a manner that the current follows a sinusoidal course in phase with the waveform of the network voltage and this is the PFC (Power Factor Correction) function performed by the block 10.
• PFC Power Factor Correction
• the reference waveform is not obtained from the input network voltage, but is made up of a perfect (tabulated) sinusoid which is adjusted in amplitude to the network voltage which is measured from time to time.
• Another highly important feature performed in block 10 in PFC mode is that of achieving loop gain which is as large as possible in order to introduce the least possible error in tracking the reference waveform, by limiting this value to a maximum permitted by the control theory combined with the sampling theorem: in conventional controllers, this entails a fixed maximum loop gain.
• loop gain may vary as a function of the phase angle of the reference sinusoid relative to its starting point.
• the maximum possible value for loop gain is established by stability constraints which are valid along the entire reference sinusoid.
• loop gain should be as large as possible in absolute terms in the first part of the sinusoid, where its gradient is steepest.
• gain could also be reduced, since the input itself allows subsequent variations which are ever more restricted until the peak is reached (angle of 90°).
• using the DSP device 7 makes it possible to modify loop gain by virtue of the instantaneous angle described by the sinusoid, in such a manner as to achieve results which are not possible using a conventional approach.
• the DSP microprocessor 7 having been adopted, it is possible to carry out "on-line” modification of the operating conditions of the device 1 in relation to the status of some variables.
• the switching energy dissipated by the power MOSFET M is proportional to the square of the voltage prevailing on each switching cycle across the parasite output capacitor of said MOSFET.
• the two different proportionality factors make it appropriate to establish a bank voltage reference which is dependent on the peak input voltage, such that losses are always and in any event minimal, so satisfying the objective of maximising conversion efficiency.
• the different bank voltage does not become a problem for the subsequent lamp supply stage, because within this process there is a lamp current controller which will thus not be dependent on the bank voltage.
• the lamp supply is current regulated makes it possible greatly to reduce the loop gain on the bank voltage, in order to minimise harmonic input components due to sampling of the output ripple.
• the PFC voltage controller stage 10 is dimensioned such that its gain is less than that calculated on the basis of the parameters in play, with the aim of minimising the amplitude of the second harmonic component returned in input (this being in consideration of the fact that, according to the sampling theorem, this second component will bring about a third harmonic component).
• This solution makes the output voltage less precise, so allowing greater ripple, but makes it possible to improve the overall dynamic behaviour of the stage.
• the possibility of evaluating the harmonic components of network current and voltage was included within the regulation process for the current drawn by the PFC block 10, such that it is possible to calculate apparent and active power, the ratio of which is the power factor. For reasons of code size and due to the fact that harmonic components beyond the 9 th are insignificant, it was decided to stop harmonic analysis at the 9th component.
• Apparent power will thus be determined from the ratio between the product of the input voltage and current calculated as the sum of harmonic components and the product of voltage and current relating solely to the fundamental: the ratio calculated in this manner represents the power factor and will be available for each network period.
• This method of calculating both apparent and active input power is mathematically scrupulous and exact and thus also makes it possible to calculate a record of the power passing through the electronic ballast 1, such that the latter is capable of "counting" consumption data over time, a function which it is difficult to achieve conventionally without adding components which are specifically dedicated to this function. b) Control and regulation of current in the lamp.
• Discharge lamps have conventionally been supplied by an alternating current which is derived from the network voltage, thus with a low operating frequency, by means of current limitation achieved with an external coil in series (reactor) which also has the purpose of stabilising current within certain limits.
• the equivalent electrical model of the lamp is particularly complex to describe, involving a strongly capacitive nature and a "diode effect" which tends to increase as the lamp ages.
• a lamp supplied in this manner actually becomes an equivalent diode which thus constitutes a short circuit when directly polarised.
• the current delivered to the lamp is at high frequency, nominally between 20 and 75 kHz.
• the modulation in frequency effected by the electronic ballast 1 is strictly within bands are completely outside those which the human eye is capable of perceiving as flickering.
• the first modulation is purely sinusoidal, the second is square wave. However, due to the effect of closed-loop control of lamp current, this second modulation will have a limited exponential effect, and this in any event allows the human eye to perceive the light to be absolutely constant and uniform.
• Discharge lamps generate light by a thermoelectric effect, i.e. by heating a gas within a bulb filled with a gaseous substance which determines the characteristics of the light emitted.
• gas is an insulating material and current cannot flow through it unless it is in a state of preionisation, a condition which is achieved by means of a high voltage electric discharge.
• the starting embodied in the electronic ballast 1 of the present invention provides always keeping the current passing through the lamp under control in order also to optimise the true starting phase itself, in such a manner as to generate high voltage pulses only when they are actually necessary.
• the method for driving is a closed-loop method, with continuous measurement of the current flowing in the lamp.
• Figure 4 shows the relevant connections between the processor 7 and the injection block 11. When the current value is above a predetermined threshold, the lamp is deemed to have been started and the current passing through it is maintained by the above- stated methods.
• the electronic ballast 1 When an HPS lamp is switched off for whatever reason, the electronic ballast 1 is capable of switching it back on immediately (hot strike restart) at the same level of luminosity as was previously delivered.
• restarting may be achieved at a low current level, as in the case of switching on a lamp which is off.
• the sequence of events is as follows: lamp lit at an emission level of ⁇ 80%; lamp switch-off and switching back on when hot.
• Switching back on may be the same as the procedure followed for cold switch-on, because the phenomenon previously described with reference to the first case cannot occur. Once switched on again, the lamp maintains its status.
• MHID metal iodide lamps cannot be switched back on when hot due to the excessive voltage required to restart the gas.
• the drop in temperature of the bulb In order to determine the time at which the lamp will again be startable, the drop in temperature of the bulb must be estimated. It has been found experimentally that a time interval of at least three minutes is sufficient to return the lamp to the minimum conditions for attempting a restart.
• the electronic ballast 1 calculates said time interval by detecting its own behaviour following a configuration carried out during installation.
• Lamp starting is a procedure which can fail for an indeterminate reason, either because the lamp might not be physically connected to the output terminals, or because the lamp has reached the end of its life and its operation cannot be extended.
• Generating a high voltage pulse effective for starting is in any event an operation which may apply excessive stress on the electronic components of the ballast 1, especially under conditions of elevated ambient humidity.
• the electronic ballast 1 is capable of recording electrical measurements in an internal archive, for example an EEPROM built into the processor 7, which may subsequently be downloaded by the remote connection via the modem 15 for optional subsequent or remote processing of the stored data by the remote unit 14.
• an internal archive for example an EEPROM built into the processor 7, which may subsequently be downloaded by the remote connection via the modem 15 for optional subsequent or remote processing of the stored data by the remote unit 14.
• the energy saving achievable by using the electronic ballast 1 may be further increased by the available light profile functionality.
• 53 light profiles are available which allow programmed operation over a period of an entire year with a granularity of one week. Within a given profile, a twenty four hour period can be subdivided at will into a maximum of eight different sections with a minimum granularity of seven minutes and thirty seconds: the firmware of the ballast 1 is capable of cyclically verifying the light level which must be delivered as a function of the corresponding time.
• the structure and functioning of the modem 15 built into the board of the electronic ballast 1 and which allows connection of any device to a concentrator with Power Line Communication functionality will now be looked at in greater detail.
• the data processing architecture is based on the fact that the modem 15 can be unambiguously addressed through an MAC (Media Access Control) address and the underlying network is a VPN (Virtual Private Network) network in which each node can be registered and authenticated.
• MAC Media Access Control
• VPN Virtual Private Network
• each electronic ballast 1 associated with a luminaire should be deemed to be a registered and authenticated node.
• the remote management unit 14 or concentrator is equipped with multiple connection layers, particularly relevant layers being the UMTS or GPRS wireless protocol, which makes it possible for the concentrator itself to become an IP node, for example with an address which is static or determined by a DHCP protocol, and so to be accessible irrespective of the geographic zone in which it is located.
• Each individual section of the communication line is managed through the PLC device 16 for routing commands and data to and from the peripheral units.
• the network constructed in this manner enables remote control of the functioning of each individual electronic ballast 1.
• the electronic ballast 1 of the present invention enables remote management of both the functioning of the ballast itself and the local area surrounding the luminaire in which it is installed.
• the electronic ballast 1 comprises an expansion port which allows connection with external devices such as a SensorBox which is a structure capable of accommodating various types of sensors, for example:
• ballast 1 is capable of managing this type of apparatus
• the items of information available in the SensorBox are exchanged with the ballast 1 and, via the latter and via the modem connection 15, are delivered to the concentrator which will store and process the information received for signalling immediate action reports, typically alarm signals, or for any optionally required subsequent processing such as for example photographs and digital images requested by judicial authorities and which are still resident in the SensorBox and associated events which have occurred beneath this specific luminaire.
• the idea of associating a SensorBox with the electronic ballast 1 also provides associating a physical or geographic position of the lamp standard or lamp post with a logical identifier (ID) which unambiguously identifies it in a database held within the remote management unit 14.
• ID logical identifier
• Each microprocessor 7 is manufactured with a globally unique "serial number" (MAC address), in the exactly the same way as occurs for the network cards now used in computers. Said number is directly diffused into the silicon and thus cannot subsequently be changed for any reason. It is thus not possible for two chips with the same MAC address to exist in the world.
• the interface protocol which has been established is thus capable of reading this code and of absolutely unambiguously identifying the device.
• Each time that a voltage is applied to a line on which a concentrator is present, the latter scans the entire line to determine the number and nature of the devices 1 capable of communicating with it, associating the various recognised IDs in an internal dynamic table.
• the table is dynamic to allow for some devices to be able to go off-line or on-line as desired or required.
• the line scan is repeated to update the table.
• This operation has a duration which depends on the number of connected devices and on the workload which the concentrator has to handle at the particular moment in time (throughput): it may be completed in a few milliseconds or several minutes. Should a concentrator not be able to recognise all the devices present on a line for reasons of noise, distance or anything else, it is possible also to request this functionality from each device present in the installation. Each of these will thus be capable of maintaining its own internal dynamic table of "contacts" with which bidirectional communication is possible.
• Complete coverage of the installation may be established by the simultaneous presence of the same contact in at least two different devices present on said line: in this manner, the length or extent of the installation may be unlimited while maintaining full coverage of the devices.
• the geographic/ logical association of a luminaire cannot automatically be determined merely by this arrangement because it is in any event necessary to create an association between each specific and fixed luminaire and a specific ID of the device 1 which is installed on said luminaire. This involves the following steps: ⁇ storing the association between the position of the ballast 1 in the given installation and the ID of the ballast itself. Guided-wave communication on the power line may conveniently be used for this purpose to acquire the ID without error from the ballast itself;
• ⁇ to permit off-line downloading of the installed associations into a database which the concentrator will access to identify the exact position of the luminaire in the area; ⁇ to permit remote reading of the association between a counter and the client then managing these logical/ geographic associations by means of the concentrator.
• Vin (network input voltage) 90-265 V AC, 50/60 Hz;
• Vout max (intermediate bank voltage) 405 V DC
• This latter value may be increased to 210 kHz to achieve a further reduction in size of the magnetic components; however, an increase in switching frequency may bring about greater electrical and electromagnetic noise problems.
• Efficiency may be further increased by introducing other components (including a magnetic component): simulation results would indicate a possible increase of 1%, but this solution is associated with higher costs.
• the critical frequency of the current loop should be as high as possible to reduce the size, volume and weight of the magnetic components and to reduce high frequency current ripple and ultimately electrical noise; there is, however, an upper limit to this value determined by the switching frequency; as is explained above, the higher is the critical frequency, the greater are the demands placed on the DSP.
• the critical frequency of the voltage loop cannot be too high if the overall harmonic distortion component is not to be degraded, an excessive increase in this value may be associated with problems in terms of overall device efficiency.
• this stage could also be functional without the PFC, but the best results are achieved with the stated values.
• the major advantage of the driving method and device according to the invention is primarily associated with the possibility of achieving substantial savings in the electric power consumption of public lighting installations.
• the electronic ballast according to the invention may be installed in existing luminaires or lamp posts, so enabling intelligent management of said luminaire or converting it into a local observation post.
• the steps for mass production of the device according to the invention entail performance of an analysis of the tolerances to be adopted with regard to device cost and desired performance. Some of the factors which have been taken into consideration for this purpose are shown below.
• the PFC stage cannot permit efficiency values of above 95%. Still at full load, the lamp supply stage cannot permit efficiency values of above 96%.

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• Circuit Arrangement For Electric Light Sources In General (AREA)
• Circuit Arrangements For Discharge Lamps (AREA)

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• 2009
  • 2009-07-02 EP EP09425259A patent/EP2271185B1/de not_active Not-in-force
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• 2010
  • 2010-07-02 CN CN2010800388587A patent/CN102498753A/zh active Pending
  • 2010-07-02 WO PCT/EP2010/004013 patent/WO2011000574A1/en active Application Filing
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